<template>
  <div>
    <router-link v-show="showAbs" tag="div" to="/" class="header-abs">
      <div class="iconfont header-abs-back">&#xe624;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      景点详情
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
    </div>
  </div>
</template>
<script>
export default {
  name: 'DetailHeader',
  components: {},
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop || window.pageYOffset || document.body.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>
<style lang="stylus" scoped>
@import "~styles/varibles.styl"
.header-abs
  position : absolute
  left : .2rem
  top: .2rem
  width : .8rem
  height : .8rem
  line-height : .8rem
  border-radius : .4rem
  text-align : center
  background : rgba(0, 0, 0, .8)
  .header-abs-back
    color : #ffffff
    font-size : .4rem
.header-fixed
  z-index : 2
  position : fixed
  top: 0
  left : 0
  right : 0
  height: .86rem
  line-height : .86rem
  text-align : center
  color : #fff
  background : $bgColor
  .header-fixed-back
    top:0
    left:0
    position: absolute
    width : .64rem
    text-align: center
    font-size :.4rem
    color : #fff
</style>
